The reliability, low cost, and ability to provide control over a wide variety of devices, systems, and processes has made electronic circuits and devices ubiquitous. However, like any other technology, electronic devices are designed as a trade-off among mutually exclusive constraints. One weakness of electronic devices is their susceptibility to performance degradation when subjected to electromagnetic interference (“EMI”). EMI is produced by a variety of sources (e.g., transformers, stray radio signals, motors, heat, and other machines and sources that generate electric or magnetic fields.) Most, if not all, electronic devices are susceptible to EMI from one source or another under the right conditions.
Electronic circuits and devices are utilized in many automotive applications. The electronic circuits utilized in automobiles are generally designed to be electromagnetically compatible with each other, such that one electronic circuit does not interfere with the functioning of a near-by electronic circuit. Electromagnetic compatibility relates to the ability of electronic and electrical equipment and systems to operate without adversely affecting other electrical or electronic equipment or being affected by other sources of interference.
In many cases EMC is achieved using what are called EMI countermeasures or sometimes EMC countermeasures. Such countermeasures either reduce or eliminate the creation of interfering signals or counterbalance or cancel the signals or their effects. As noted, EMI countermeasures may cause excessive heat. Generally, electronic circuits are designed to accommodate a maximum thermal load. If the circuits are subjected to conditions beyond their limits, they will malfunction. In addition to heat caused by the operation of electronic and electric devices, the environmental temperature and other heat sources may combine to cause malfunctioning of electronic components and electronic circuits.